Urgent: Please help: Buffering capacity question

[Roan Art]

Roan, those are 2 German blue rams, not gouramis,and no I did not QT them, do you think thats whats wrong with the fish, they're :sick: ?

Sorry, I meant rams.

Yes, very possible the fish are sick. As to whether they came that way or something in the tank is making them ill, that's what we have to figure out. According to your readings you are showing about .1 nitrites. Not good.

How often are you doing water changes and how much? Could you test your tap water and post the readings as well?

Now the cories are dashing to the top more frequently and the bristlenose pleco is just hiding in 1 corner and not coming out for food as he used to do

Top dashing is typical cory behavior. However, if you have a pump and bubble wand, it won't hurt to put that in while we figure this out.

Also, when I look at the water from below (and believe you me I looked at that tank from every angle), there is a film on the surface like a faint rainbow 'oil spilled on water' effect? What could that be? I looked everywhere to see if there was a dead fish anywhere but couldn't see any.

Hrm.

Is this a planted tank where you are keeping the surface as still as possible to keep CO2 in? What kind of filter(s) are you using? Where do you have them situated?

Please aerate and get some gas exchange going. Lemme know if the fish behavior changes when you do so -- especially with the rainbowfish. Keep an eye on him. He's your O2 indicator. If he starts moving away from the surface and playing in the bubbles and acting more normal, then you don't have enough O2 in the tank. If he doesn't, then we try something else.

We'll be able to rule some stuff out once we get the KH reading. Don't forget to test your tank and tap for everything.

Roan